[-next,v5,17/22] arm64/ptrace: Return early for ptrace_report_syscall_entry() error

Commit Message

Jinjie Ruan Dec. 6, 2024, 10:17 a.m. UTC

As the comment said, the calling arch code should abort the system
call and must prevent normal entry so no system call is
made if ptrace_report_syscall_entry() return nonzero.

As the generic entry check error for ptrace_report_syscall_entry(), in
preparation for moving arm64 over to the generic entry code, also return
early if it returns error.

Signed-off-by: Jinjie Ruan <[e-mail]>
---
 arch/arm64/kernel/ptrace.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

Patch

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 23df2e558fe9..b53d3759baf8 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -2298,10 +2298,10 @@  enum ptrace_syscall_dir {
 	PTRACE_SYSCALL_EXIT,
 };
 
-static void report_syscall_enter(struct pt_regs *regs)
+static int report_syscall_enter(struct pt_regs *regs)
 {
-	int regno;
 	unsigned long saved_reg;
+	int regno, ret;
 
 	/*
 	 * We have some ABI weirdness here in the way that we handle syscall
@@ -2323,9 +2323,13 @@  static void report_syscall_enter(struct pt_regs *regs)
 	saved_reg = regs->regs[regno];
 	regs->regs[regno] = PTRACE_SYSCALL_ENTER;
 
-	if (ptrace_report_syscall_entry(regs))
+	ret = ptrace_report_syscall_entry(regs);
+	if (ret)
 		forget_syscall(regs);
+
 	regs->regs[regno] = saved_reg;
+
+	return ret;
 }
 
 static void report_syscall_exit(struct pt_regs *regs)
@@ -2355,9 +2359,11 @@  static void report_syscall_exit(struct pt_regs *regs)
 
 int syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long flags)
 {
+	int ret;
+
 	if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) {
-		report_syscall_enter(regs);
-		if (flags & _TIF_SYSCALL_EMU)
+		ret = report_syscall_enter(regs);
+		if (ret || (flags & _TIF_SYSCALL_EMU))
 			return NO_SYSCALL;
 	}